Evolution, as a function of the tolerance factor increasing of the unit-cell parameters (a), the unit-cell volume (b) and the monoclinic angle ( $\beta$) (b) at room temperature of the synthesized materials $\mathrm{Ca}_{2} \mathrm{MSbO}_{6}(\mathrm{M}=\mathrm{Nd}, \mathrm{Eu}, \mathrm{Gd}, \mathrm{Dy}, \mathrm{Ho}, \mathrm{Er}, \mathrm{Tm}, \mathrm{Yb}$ and Y
Evolution, as a function of the tolerance factor increasing of the unit-cell parameters (a), the unit-cell volume (b) and the monoclinic angle ( \beta) (b) at room temperature of the synthesized materials \mathrm{Ca}_{2} \mathrm{MSbO}_{6}(\mathrm{M}=\mathrm{Nd}, \mathrm{Eu}, \mathrm{Gd}, \mathrm{Dy}, \mathrm{Ho}, \mathrm{Er}, \mathrm{Tm}, \mathrm{Yb} and Y